Guest API WebSocket connection fails with 403 after successful OAuth token generation

Looking for advice on building a custom chat UI using the Genesys Cloud Guest API instead of the standard widget. I am attempting to implement the WebSocket-based guest connection flow as described in the developer documentation. My backend service successfully generates an OAuth access token using the client_credentials grant type with the webchat:guest:create scope. However, when I attempt to establish the WebSocket connection to the endpoint wss://api.mypurecloud.com/webchat/v1/guest/connect, the connection is immediately rejected with a 403 Forbidden status code in the HTTP upgrade response headers.

I am using Node.js with the ws library on the client side. I pass the Bearer token in the Authorization header of the WebSocket handshake request. The code snippet for the connection attempt is as follows:

const WebSocket = require('ws');
const token = 'eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...';

const ws = new WebSocket('wss://api.mypurecloud.com/webchat/v1/guest/connect', {
 headers: {
 'Authorization': `Bearer ${token}`,
 'Content-Type': 'application/json'
 }
});

ws.on('error', (err) => {
 console.error('WebSocket error:', err.message);
});

ws.on('close', (code, reason) => {
 console.log(`Connection closed with code ${code}: ${reason}`);
});

The error log shows: WebSocket error: Unexpected server response: 403. I have verified that the token is valid by calling /api/v2/authorization/userinfo which returns a 200 OK. I am confused about whether the Guest API requires a different authentication method or if I need to include specific query parameters in the WebSocket URL. The documentation mentions that the token must have the correct scope, which I believe I have configured. Is there a specific JSON payload required in the initial WebSocket message to authenticate the guest session, or is the handshake itself failing due to a missing header? I am struggling to find examples of successful WebSocket handshakes for the Guest API in the forum.

Pretty sure the issue often stems from using client_credentials for guest initialization. That grant type is intended for server-to-server communication, not end-user sessions. You need to use the password or authorization_code grant to generate a token that binds to a specific user context, or rely on the Guest API’s ephemeral token generation endpoint directly.

Here is the correct flow using the Guest API to get a valid token for the WebSocket:

# 1. Create guest identity
POST /api/v2/guests
Content-Type: application/json

{
 "name": "Test Guest",
 "email": "[email protected]"
}

# 2. Extract the 'token' from the response body
# 3. Use this token in the WebSocket query string, NOT the OAuth Bearer token
wss://api.mypurecloud.com/api/v2/guests/webchat?token={guest_token}

The WebSocket handshake fails with 403 because the server expects a guest-specific session token in the query parameters, not an OAuth bearer token in the headers. Ensure your backend extracts the token field from the /api/v2/guests response and passes it directly to the client.

The official documentation states the webchat:guest:create scope is for server-side token generation, not direct WebSocket authentication. You must exchange that token for a guest session ID first.

curl -X POST "https://api.mypurecloud.com/api/v2/conversations/webchat/guestsessions" \
 -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
 -H "Content-Type: application/json"